I believe that my UPS was built in 1991. They just don't build them like they used to. It still manages to get me around 20 minutes of power
Then it might also have something to do with it being a fairly large ICL (anyone ever encounter them before they were taken over by (I believe) Fujitsu?) UPS, connected to just about the largest single processor 486 in existance (I only keep that part because it looks impressive, and it works as a nice thermometer).
I think I picked it all up for about $AU20 a few years back.
edit:
If anyone is interested, I found I have an image of my ups setup, it definately gives an idea as to the physical size of it all
I hope that works.